I don’t get why everyone isnt using those
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This?
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BC no one knows how to set it up and program the liion charge curve
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you don’t need to program any curve, it’s automatic
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It automatically does the curve for whatever voltage you set it at?
yep
you set end voltage, amperage, it does the rest
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Oh shoot I must have been looking at an older version a while ago then. There was a thread with this model in it somewhere right?
Regardless of how big the battery is? Nonsense.
Someone please explain the purpose of active management vs passive management.
What is the point?
What’s 1c x 120? in amperes? 170 amps or so?
Isn’t that how it’s figured out? How come no one is talking about the size of the battery. I’m in the middle of a 12s10p build, and there’s just no way .85 ma’s of current is enough to quickly balance the pack.
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Yeah, the bigger the battery the slower the unbalance will happen because the small cell to cell variations get smoothed out
Look a Tesla BMS, they have a huge amount of parallel cells, charge at a current immensely higher than we charge, yet you just have small SMD resistors on the board, I remember seeing a while ago that the balance current was 200 mA
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This doesn’t make sense to me. It could take a week to balance a Tesla battery with that thing. Probably longer. So far it has been explained to me- that we simply don’t need to sink that much power because the batteries will never get that out of balance to begin with. I just don’t like this logic.
You could set yourself up for a situation in which you can charge faster than balance, and that makes 0 sense to me. Tesla also has Tesla fuses, we don’t. I don’t understand why we’re being so conservative on these balance numbers, nor do I understand the purpose of active management when compared to passive management- it still uses lifespan to move power around. In fact, it’s probably more abusive than just turning the excess power into heat.
How can I charge a 12s4p battery at 15 amps without being concerned about the battery charging before it is balanced?
You can not fully charge a battery that is out of balance.
Where would one find instructions on how to DIY one of these nifty CC CV chargers?
That is the think I’m trying to say, a good quality battery will hardly go out of balance, to the point that this small amount of balancing is enough to keep it in check
A pack that is poorly made, with doubtful quality cells will certainly get out of balance
I’ve personally run a pack/ with quality cells for more than 100 cycles and the difference between lowest and highest parallel group was less than 0.01 V
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Right, well. I’m not the least bit worried about a new pack. It would be towards the end of its lifecycle that balancing became a concern.
In order to figure out maximum charge rate, we just multiply the c-rating by the number of cells in the pack, correct? Most people are charging at rather low rates, but I expect this to change drastically in the coming years. Quick charging these packs will become a thing, imo. Most people are charging at like 4 amps, and that’s incredibly low as opposed to what the cells can handle.
Currently, I don’t run any sort of BMS or balance circuit, on my Trampa, because it just doesn’t get out of balance, -it’s too new, but it will eventually need it.
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@ShutterShock @MYKC I’ll start a thread later today or tomorrow, didn’t realize there was so much confusion 🤷😋
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Thx! I guess I always thought it was more complicated than it actually is. I have built a power supply before too lol
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I know it’s easy to get stuck on something that doesn’t make sense. Been there. But often it is better to trust the experts in the field or become the expert and do experiments and show why your system is better.
The whole point of balancing is so that the max voltage is same to avoid overcharge. They are not meant to keep actively balancing all the times. It is wasteful both in terms of energy and also money to build that kind of board. When the lowest voltage of a parallel group reaches allowed minimum the battery pack doesn’t allow further discharging. That’s all. Rinse and repeat, until there is very little effective capacity left.
And BTW, when a battery pack is assembled, it is very important that the cells are all charged to the same voltage and have same capacity (with some allowed tolerance).
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I think the only reason Tesla can get away with that BMS is because they have cell level fusing.
Fusing is done to deal with a failed cell. A short-circuited cell. Not cells getting out of balance with rest of the pack.
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